Urban greenness and mortality in Canada’s largest cities: a national cohort study

Eleven authors published the following article in The Lancet Planetary Health, October 2017, pp.  e289-e297:

Urban greenness and mortality in Canada’s largest cities: a national cohort study

From the Summary:

“We … undertook a national study in Canada to examine associations between urban greenness and cause-specific mortality.”

“We used data from a large cohort study (the 2001 Canadian Census Health and Environment Cohort [2001 CanCHEC]), which consisted of approximately 1·3 million adult (aged ≥19 years), non-immigrant, urban Canadians in 30 cities who responded to the mandatory 2001 Statistics Canada long-form census. The cohort has been linked by Statistics Canada to the Canadian mortality database and to annual income tax filings through 2011. We measured greenness with images from the moderate-resolution imaging spectroradiometer from NASA’s Aqua satellite. We assigned estimates of exposure to greenness derived from remotely sensed Normalized Difference Vegetation Index (NDVI) within both 250 m and 500 m of participants’ residences for each year during 11 years of follow-up (between 2001 and 2011).”

“We showed significant decreased risks of mortality in the range of 8–12% from all causes of death examined with increased greenness around participants’ residence. … Greenness associations were more protective among men than women … and among individuals with higher incomes … and more education.”

“Increased amounts of residential greenness were associated with reduced risks of dying from several common causes of death among urban Canadians. We identified evidence of inequalities, both in terms of exposures to greenness and mortality risks, by personal socioeconomic status among individuals living in generally similar environments, and with reasonably similar access to health care and other social services. The findings support the development of policies related to creating greener and healthier cities.”

Media report: http://www.cbc.ca/news/health/green-spaces-lower-mortality-1.3150812> (October 13, 2017)

For an excellent collection of research papers on human health benefits of natural landscapes, go here: http://lhhl.illinois.edu/all.scientific.articles.htm, the web site of the Landscape and Human Health Laboratory of the University of Illinois at Urbana-Champaign.  Ann Coffey writes: “In my 30+ years of greening school grounds, I never came across any research elsewhere that could better the work done by LHHL. I made several attempts to interest the city and school boards in LHHL’s work, but I suspect it largely fell on deaf ears.”

For earlier entries in the Readings section related to health, go here and here and here.